NEW BEDFORD (CBS) – A loaded AR-15 style police rifle was stolen from the trunk of an unmarked New Bedford police vehicle, the chief has confirmed.

Police Chief David Provencher confirmed the theft and vowed to use every resource to find the weapon.

He plans to work with federal, state and local law enforcement agencies to figure out who was responsible for the theft.

“There is no higher priority to us than the location and recovery of this stolen firearm,” New Bedford Police Chief David Provencher said in a statement. “It is my promise to this community that we will do everything humanly responsible to recover this weapon. We will not rest, we will leave no stone unturned. Those responsible should be aware we are coming for them and it is in their best interests to return the weapon.”

The chief would not say where or when the gun was stolen.

New Bedford Standard Times cited sources saying the rifle is kept in a case that is bolted to the trunk and secured with a combination lock. They reported the case was left behind.